What about the Southern Goldwater-Humphrey Counties:
5 in VA
16 in SC
1 in GA
2 in AL
8 in MS
3 in LA
Some of those can rather easily be explained by passage of the voting rights act shifting political majorities from white voters in power due to jim crow to black voters now able to vote due to the voting rights act of 1965, but some of these Counties have little to no black population in them. What happened there?
Admittedly, I would have left a blank presidential ballot in 1964 and then voted for Humphrey in 1968 if I was alive and old enough to vote back then because both Johnson and Goldwater were absolutely terrible.
What were the Goldwater-Humphrey counties that didn't have a large block of black voters?